Locally owned and operated in Colorado since 2002--Everything You Need to Go Solar!

Solar Panel Store Blog — Learning Solar

RSS
Solar Home Grid-Tie System Sizing Part 1: Using a Utility Bill

Solar Home Grid-Tie System Sizing Part 1: Using a Utility Bill

Grid-Tied (a/k/a “grid interconnected”) solar systems are the most common and simple types of solar electric systems homeowners install. These complete solar power systems are connected to the utility grid and generate electricity while the sun is shining and the grid is running. If the system produces more energy than your home uses, then the system sends (sells) the excess energy back to the grid, which would offset any electricity you buy from the utility at night (check with your utility provider for details, as these policies vary). 
If you consume more energy than your system is able to generate, then the utility would supply your additional energy demand as usual. Grid-tied solar panel power systems are great for reducing your energy bill.

Sizing a system can seem confusing at first, mostly due to the flexibility of sizing a grid-tie system. We can base a system on a certain amount of production to off-set current usage, to fit into a budget, or to just take advantage of the roof-space available to install the solar panels on. 

Figuring out the size of system to offset current usage is pretty straight forward and simple though, so we will start the series off with this. Here is an easy method to help you figure out the correct solar panel array size for your home.

Step 1: Find your monthly average electricity usage from your electric bill.This will be in kilowatt-hours (kWh). Due to air conditioning, heating and other seasonal usage, it is a good idea to look at several bills. You can add the typical summer, fall, winter and spring bills and divide by four to find the average monthly usage.

Step 2: Find your daily average electricity use. Divide the monthly average number of kWh use by 30 (days).

Step 3: Find your location's average peak sun hours per day. Find what is known as an insolation map, or average sun hour list. For example, Colorado is around 5 peak sun hours. Alternatively, a PV Watts is a great online tool from NREL that will provide great insight for month by month and average solar radiation for your specific location. (https://pvwatts.nrel.gov/)

Step 4: Calculate the system size to provide 100% of your electricity. Divide your daily average electricity use by average sun hours per day. For example, if the daily average electricity usage is 30 kWh, and the site is in Colorado, system size would be: 30 kWh / 5 h = 6 kWh. It's a good idea to multiply this number by 1.15 in order to account for factors such as inverter efficiency, dirt or pollutants that may accumulate on panels, etc., if you want to cover all of your use. (One of our solar home packages in the 7 kW range would be great for this!)

Take a look at some of our pre-configured grid-tie packages here, or contact our sales team for more information, we are eager to help out and provide you with everything you need to go solar! 
Deciding on the Best Solar Panel System for your RV

Deciding on the Best Solar Panel System for your RV

RV Solar Panels

Shopping for RV solar systems can be a drag if you don't have the right knowledge on what you will need for your situation. Solar panel mounting tends to be difficult if you've never done it before but we're here to help you along every step of the way.

Steps to deciding on the right solar system for Rv's

1) Decide what kind or RVer you are 

First off, you will need to categorize your RV usage - that is, are you a full-timer? Or are you someone who just gets away for the weekends? If you fall in either of these categories, you'll want to really do the math before investing in a solar panel system. But if you're someone who tends to go away off the grid for extended periods of times but you're not a full-timer, then you should consider one of our solar electric systems. Why is this the most likely scenario where your investment will really pay off? Because the weekend warrior will always have enough battery to get through the weekend. And full-timers will most always find somewhere to doc where power is supplied at the RV park, and you're going to end up paying for that electricity anyway with your park fees. Same goes for marine solar, you need to ask yourself whether you'll have shore power or if you'll be spending extended periods on the water without a generator.

2) Decide how much solar power you will need

Electricity consumption differs from user to user. For example, if you have a larger RV with a microwave, TV, lighting, water pumps and electrical hookups for other devices, you'll need a different RV solar kit than someone who has a smaller RV that needs to run less lighting and perhaps only a water pump. So figure out how much power you'll consume in (example, 4 hours of TV might take 600 watts/hours per day, lighting = 350, refrigerator = 5,000). Then you'll need to know how much storage or battery capacity you'll need on board. From there, you'll be able to back into the numbers and get the proper setup.

An example might be needing to generate 2,000 watts per day so a nice 400 watt system would be the perfect system for someone who needed to power enough to use for that day on into the evening. Of course if you travel when you know you won't have full days of sun and some cloudy days, you'll probably want to increase the capacity for charging. It won't be too long that you'll break even after looking at a gasoline powered generator running to generate that kind of power, not to mention the impact on the environment.

3) Decide on the RV solar system or Marine system you'll need

Based on the few tips above, we'd love to help you decide on exactly what you need. Just give us a call and we'll gather your requirements and help you find the perfect, tailored solution to your portable solar panel needs.

RV Solar Kits